1. Technical Field
The present invention relates generally to wireless communication systems; and more particularly to a wireless communication system in which a mobile switching center that serves a mobile unit is apprised of the termination access type of a call delivered to the mobile unit, the serving mobile switching center generating a call detail record for the call which includes the termination access type, the mobile unit, the duration of the call and additional information, the call detail record later used to generate a bill for the subscriber of the mobile unit.
2. Related Art
Cellular wireless communication systems are generally known in the art to facilitate wireless communications within respective service coverage areas. Such wireless communication systems include a "network infrastructure" that facilitates the wireless communications with mobile units operating within a service coverage area. The network infrastructure typically includes a plurality of base stations dispersed throughout the service coverage area, each of which supports wireless communications within a respective cell (or set of sectors). The base stations couple to base station controllers (BSCs), with each BSC serving a plurality of base stations. Each BSC couples to a mobile switching center (MSC) which also couples to the PSTN, the Internet and/or to other MSCs.
A wireless mobile unit operating within the service coverage area communicates with one or more of the base stations. The base stations route the communications to the MSC via a serving BSC. The MSC routes the communications to another subscribing wireless unit via a BSC/base station path (which may be the same BSC/base station path when the communications are with another subscribing unit serviced by the same base station) or via the PSTN/Internet/other network to terminating destination.
Various operating standards have been developed to standardize wireless communications. The wireless communication operating standards include, for example, the Advanced Mobile Phone Service (AMPS) standards, the Global Standards for Mobility (GSM), the Code Division Multiple Access (CDMA) and the Time Division Multiple Access (TDMA) standards. A standard that is employed in North America for interconnectivity of MSCs is the IS-41 standard. These operating standards set forth the technical requirements that facilitate compatible operation between equipment of differing vendors.
In a cellular wireless communication system, each MSC is operated by a particular service provider and services communications over a fairly large geographic area. A large number of mobile units are serviced by this MSC. Each MSC serves as a home or "originating MSC" for a number of mobile units. The mobile units are assigned a permanent telephone number that, when routed via the PSTN, reaches the originating MSC. The originating MSC then performs call routing in an attempt to deliver the call to the mobile unit. As part of call routing, the originating MSC accesses the Home Location Register (HLR) servicing the mobile unit. The HLR provides the identity of a MSC currently serving the mobile unit (the "serving MSC").
If the mobile unit is operating with the coverage area of a base station supported by the originating MSC, the originating MSC is also the serving MSC. In such case, the originating MSC initiates a page to the mobile unit, the mobile unit responds to the page, and the call is completed. However, if the mobile unit is not being served by the originating MSC, but instead is being served by another MSC, a serving MSC, inter MSC operation is initiated. In such case, the originating MSC sends a locate request to a HLR servicing the mobile unit. In response, the HLR sends a route request to the serving MSC. Subsequently, the call is routed through the serving MSC to the mobile unit. Such operation is often referred to as call termination while "roaming".
While such seamless operation is greatly appreciated by the subscribers, many difficulties arise from these roaming operations. One such problem relates to billing procedures. Bills are generated for the subscriber of the mobile unit by its service provider (who operates the originating MSC). These bills are typically generated based upon call detail records (CDRs) generated by the originating MSC that identify the mobile unit and its call duration. However, when the mobile unit is roaming such that it is served by another MSC (the serving MSC), a CDR is generated by the serving MSC as well. The CDR created by the serving MSC identifies the mobile unit, the caller and the call duration. However, in many billing plans offered by service providers, the billing structure requires substantial additional information. This information is not included in the CDR of the serving MSC. Thus, an accurate bill may not be produced without cross-referencing the CDRs produced in the originating MSC with CDRs produced in the serving MSC.
Thus, there is a need in the art for a wireless communication system in which billing can be generated based upon the information collected and stored by a serving MSC that services a roaming mobile unit.